1. Field of the Invention
The present invention relates to a spreading anchor including a sleeve having an expansion region provided with longitudinal slots and an axial bore having a conical shape in the expansion region of the sleeve, and a spreading member having a conical profile at least along a portion of its longitudinal extent and displaceable in the axial bore upon radial expansion of the sleeve expansion region.
2. Description of the Prior Art
A conventional multiple-use spreading anchor of the above-described type, which is known for a long time, includes, as discussed above, an expansion sleeve having an expansion region and a conical axial bore in the expansion region, and a mostly conical spreading member which is displaceable in the axial bore of the sleeve upon a radial expansion of the expansion region of the expansion sleeve. In this known spreading anchor, the axial bore of the expansion sleeve has its diameter reduced to the front, with respect to the setting direction, end of the expansion sleeve. The spreading member is driven into the conical section of the axial bore of the expansion sleeve by axial impacts thereon. The expansion sleeve is anchored in the bore upon a radial expansion of the expansion region. According to one embodiment of the conventional spreading anchor, the axial bores expands conically toward the sleeve front end, and the spreading member is held at the front end of the sleeve. For anchoring the spreading anchor in a bore, the sleeve is driven over the spreading member which is supported against the bore bottom. The sleeve expands while being driven over the spreading member. After the expansion sleeve has been anchored in the bore, an anchor rod, which serves for attachment of a constructional component, is connected with the sleeve. The expansion sleeve is provided, to this end, with an inner thread in the rear region of the axial bore. The anchor rod is provided with a corresponding outer thread.
For forming a connection with this spreading anchor, it is necessary first to anchor the expansion sleeve in the bore. Only then can an anchor rod or a threaded rod be screwed into the expansion sleeve for attaching a constructional component. At that, the inner thread provided in the rear end region of the expansion sleeve and the outer thread of the anchor rod must be matched with each other with regard to their diameters. If, e.g., the expansion sleeve has a metric inner thread with a particular diameter, only an anchor rod with a corresponding metric thread and a corresponding diameter can be attached to the sleeve. With this conventional spreading anchor, it is not possible to attach an anchor rod having, e.g., a British Standard Whitworth (B.S.W.) thread to an expansion sleeve having a metric thread. It is also not possible to use, with this conventional spreading anchor, conventional reinforced steel rods having a radial or thread-shaped profile formed on its outer surface.
According an object of the present invention is to provide a spreading anchor which would provide for a simple and quick formation of an attachment point. The anchoring of an expansion sleeve in a bore in a separate operational step before attachment of an anchor rod should not be any more necessary.
A further object of the present invention is to provide a spreading anchor which would create conditions for attachment of anchor rods having outer surfaces with differently shaped profiles. The spreading anchor should also have a certain allowance for a spread of outer diameters of the attachable anchor rods. The spreading anchor should also have a secondary expansion capability to insure an adequate anchoring in case of crevices in the structural component.